AnaSpec is pleased to announce the release of the industry’s first and
longest wavelength FRET based Cathepsin K assay, the SensoLyte®
520 Cathepsin K Assay Kit. Optimized for detecting Cathepsin
K activity, this kit contains a novel internally quenched
5-FAM/QXL™ 520 FRET substrate. Upon cleavage of this FRET
substrate, two separate fragments are generated resulting in the release
of 5-FAM fluorescence. Fluorescence can be monitored at Ex/Em= 490/520 nm. Increase
in fluorescence is proportional to the Cathepsin K activity. The SensoLyte®
520 Cathepsin K Assay Kit is AnaSpec’s most specific assay kit in its catalog.

For biological
samples containing mixed cathepsins, AnaSpec offers the SensoLyte® Rh110 Cathepsin K Assay Kit. Spectrally
similar to the SensoLyte 520 assay kit, the Rh110 substrate is cleaved by Cathepsin
L (if present in samples) at a faster rate than the FRET substrate provided
in the 520 kit.

Both kits
include long wavelength fluorescent dyes, 5-FAM and Rh110, that are subject
to less interference by the autofluorescence of components in biological samples
and test compounds.

Cathepsin
K is a cysteine protease that plays a role in the degradation of protein components
of the bone matrix during bone resorption.1Produced by bone resorbing
macrophages and synovial fibroblasts, Cathepsin K cleaves proteins such as collagen
type I, collagen type II and osteonectin.2
It has potential as a drug target in autoimmune diseases and osteoporosis.3,
4